1. Field of the Invention
The present invention relates to a bending process estimation apparatus, a bending process estimation program, and a bending process estimation method that estimate the result of a bending process.
2. Description of the Related Art
A bending process for plate forming using a laser beam has been used in a situation where high processing accuracy is required. This is a technique that irradiates a plate with a laser beam to cause thermal gradient in the thickness direction of the plate to thereby bend the plate. For example, this laser bending process for plate has been used in the case where deviations in the pitch and roll angles are corrected in a suspension process for HDD (Hard Disk Drive).
Conventionally, at the time of launching a manufacturing process for a new model, a large number of samples are used, a laser beam is irradiated onto the samples (workpiece materials) under various process conditions to acquire the bending amounts, and thereby a relationship between the process condition and bending amount is determined based on a large amount of acquired data. At this time, a laser beam is irradiated onto various positions of the workpiece under various irradiation conditions to thereby find a relationship between process/correction condition corresponding to process/correction position and process/correction amount. In order to find out a process/correction condition under which a desired bending amount can be obtained as described above, a great deal of experience and know-how is required. If past experience or know-how has been accumulated, it is possible to make use of it for setting process/correction condition for a new model. On the other hand, however, if past experience or know-how has not been accumulated, many more work units are required to set the process/correction condition. The term “process condition” used here includes laser output, irradiation diameter of a laser beam onto a plate, moving velocity of a laser beam, and the like.
As a prior art related to the present invention, Jpn. Pat. Appln. Laid-Open Publication No. 2002-239633 is known. In the method of creating a process condition database for plate process machine disclosed in the publication, calculation of a contribution ratio and generation of new explanatory variable are repeated based on the explanatory variable used in determination of control amount of the plate process machine to obtain a regression expression, and the process condition database is created using the regression expression.
However, in the above method of finding the process condition using a large number of samples, an unacceptable large number of hundreds of samples need to be prepared, for example. In order to prepare such a large number of samples, it is necessary to consider cost of materials for sample preparation, separately from the problem of the work units. Particularly, manufacturing unit cost of samples is higher than that at the time of mass production, so that the problem of cost of sample preparation can not be ignored. Further, there is a possibility that samples required to find out the process condition cannot be prepared. Furthermore, it is impossible to obtain data for determining the process/correction condition at all in a state where an actual workpiece has not been completed. Accordingly, it is impossible to estimate how much bending can be done by the irradiation of a laser beam or how much the pitch angle is changed when the roll angle is corrected.
Further, in the future, the size of a workpiece is expected to be further reduced to limit laser beam irradiation area, so that it becomes necessary to design the workpiece with a laser bending process applied thereto in mind.